This field of invention relates generally to fluid impulse Pelton turbines, and specifically to a system and method to increase the overall efficiency of the Pelton turbine.
Many different systems and devices are known and in use for generating electrical power. Such systems include hydroelectric systems, typically associated with water dam. Hydroelectric systems generate electric power by permitting water to drop from one level to another, and then harnessing the energy of the elevational change to drive a turbine. The turbine, in turn, drives a generator that produces electrical power that can be controlled, filtered, and output to a power grid. One type of hydroelectric turbine is commonly referred to as a Pelton turbine.
A conventional Pelton turbine is a fixed blade turbine having a runner with curved blades, called runner blades, disposed in a protective casing. The runner of the turbine spins, driven by high-speed jets of water flowing from a higher elevation to a lower. The incoming water typically is provided through pipes, or penstocks and, depending on the width of the runner, water is directed through a manifold arrangement, referred to as a distributor, providing multiple outlets for the water to impact the runner. Water is metered to the runner from the distributor through needle valve injectors, which send jets of water into the turbine blades or buckets to turn the runner. A surrounding casing controls the splashing and exhaust of water.
Efficiency of a Pelton turbine is affected by the efficiency of the needle valves used to meter water flow from the distributor to the runner. If the water flow is decreased in a conventional Pelton turbine, the efficiency of the turbine reduces. In general, the water jet stream is directed towards the runner blades, thereby producing a force on the runner blades, which in turn results in torque of the shaft attached on the runner and used to drive the generator shaft. Thus, the available head (generally the elevational drop through the turbine) is converted to kinetic energy at the injectors. A typical efficiency of a Pelton turbine may be considered approximately 90% at the rated output, and can be maintained relatively constant even under part load operation in the case of a multiple jet design.
There is a need, therefore, for an improved technique for increasing the overall efficiency of the Pelton turbine. There is, at present, a particular need for a technique, which can be employed in a straightforward manner to increase the overall efficiency of a Pelton turbine to address the drawbacks in heretofore known systems.